Fig. I. — Diagnim illustrating Weismann's theory of germinal con- 

 tinuity. Three generations are represented, with cells of germ plasm 

 shaded, and those of body plasm unshaded; germ plasm continuous from 

 generation to generation, carried over from parent to ofTsping by z\gote 

 (Z); impossible for body plasm to perpetuate itself into a second 

 generation. 



